We Will Never Forget The Mercedes SLR McLaren And Neither Did Renntech Who Made It Super Fast Again

Mercedes-Benz SLR McLaren started it all – OK, with its nemesis Porsche Carrera GT – and now we are basking in the glory of supercars of today who are, definitely, the most outstanding achievements of the engineering of today. The SLR McLaren life spanned for eight years more or less. In that time 1.400 units left the factory (much less than planned 3.500 units) with McLaren and Mercedes-Benz producing a multitude of different versions.


True, the first cars started as machines powered by 626hp engines (with some rated at 650hp in the best 722 version), which is, by today’s standards quite underwhelming. That is huge power for sure, but even the Audi supercar – the R8 V10, almost touches that number, let alone mid-sized Ferrari or McLaren cars. Heck, even a BMW M5 has a version with 600hp.


So, the owners of this handsome and quite amazing machines are not perfectly happy with the power and with the performance its prized possessions can deliver. That is where the tuning shops come in. This time, the Renntech, famous tuner from Lake Park, Florida took on the challenge to tune up the hand-built, 5,439 ccm (331.9 cu in), supercharged, all-aluminium V8 engine. As one of the most potent engines of all time, the mighty V8 was a real technological artwork at the start of the new millennium. Renntech did have to do some really amazing tweaking. The changes include an ECU upgrade. These days you cannot read an article about tuned cars without seeing ECU remaps and upgrades.


In general, an ECU remap actually allow the engine to have air to fuel ratio and ignition timing sequence at levels which give out as much power as possible. With richer air to fuel ratio (richer than 14,7 air parts to 1 fuel part – or in plain English – less air and more fuel), the engine will definitely have a bigger bang. Moreover, with the tricked out ignition timing (the time when a spark ignites the mixture making a bang and move the piston down the cylinder), the engine can be made to produce even more power. If you ask why don’t the manufacturers do this right at the factory, the answer is fuel consumption and emission ratings. With the ECU remap, we are usually using more fuel to produce more power and to ignite it under higher pressures.


In this case, the ECU upgrade, with a new pulley, a dual intercooler pump, and a stainless steel sports muffler, the engine produces 748hp and 748 lb-ft of torque. This is 100hp more in comparison to the most powerful 722 SLR (true, Mercedes-Benz and McLAren produced a racing SLR with an engine developing 690hp, but it was not going on the public roads).


After giving the SLR the much-needed power upgrade, Renntech updated the rear differential. New limited slip diff will make it possible for this magnificent old supercar to hold a candle to supercars of today. It is quite amazing how that old M155 V8 can be improved only by a few interesting upgrades. Now, this engine is as powerful as the one in the 2017 Lamborghini Aventador SV and that is staggering, to say the least.

Back in its heyday, the Mercedes-Benz SLR McLaren accelerated to 62 mph in 3,4 seconds and was capable of hitting more than 205 mph. With the new upgrade, freshened up cavalry under the bonnet and limited slip diff, it’ll do better for sure.

Categories: Production Cars

Safet Satara
About Safet Satara

I do not have spare time. All there is is car time. 12 years and counting. I am a Central European gearhead, but you are probably thinking - aaa a disposable Borg drone! Well, actually, I like to dress up like James Bond too. The only thing I need to be him is an Aston Martin (and I love DBS more than DB5 because, reasons). That's something I guess.